Device and method for access to interior body regions

ABSTRACT

A device and method is provided to gain access to interior body regions. The system includes a safety needle, a stylet assembly, a blade assembly, an obturator assembly, a cannula assembly, a handle assembly, an actuator assembly, and a lock assembly. The safety needle accesses an interior body region. The actuator assembly, lock assembly, and handle assembly interact to expose the blade assembly, after which the blade assembly expands the pathway created by the safety needle. The obturator then further expands the pathway and delivers the cannula assembly to the desired location. The safety needle, obturator assembly, blade assembly, handle assembly, actuator assembly, and lock assembly are removed, leaving the cannula assembly in place for future procedures.

TECHNICAL FIELD

The present invention relates to devices and methods to access interiorbody regions. More particularly, it relates to devices and methods usedto create space to insert a tube into a patient.

BACKGROUND

Embodiments of the invention relate to devices to create access tointerior body regions and methods of using the devices.

There are many instances in which a practitioner must access the chest,abdomen, or pelvis, and insert a drainage tube, or chest tube. Examplesof these instances include: collapsed lung, lung infection, bleeding inthe chest cavity, fluid or air buildup due to other medical conditionsor trauma, and prior surgery.

The traditional way of inserting a chest tube begins with thepractitioner prepping the side of the body for the chest tube bysterilizing the area. Using a scalpel, the practitioner then makes asmall incision (skin nick), between the ribs closest to the desiredlocation in the chest. Then, using a combination of blunt dissection andsurgical clamps, the practitioner will slowly open the space and extendit into the chest cavity. Once the practitioner confirms she has reachedthe desired space, the chest tube is inserted and sutured in place toprevent slippage.

Critics claim that the traditional method of chest tube insertion isbarbaric and does not take advantage of advances in technology that canmake the insertion process safer and more effective. Some companies havedesigned devices, called trocars, to facilitate safer and easier chesttube placement without using multiple, separate components.

Many groups of trocars include a combination of an access needle, anobturator and a dilator. The doctor advances the device against the skinand interior body regions using the access needle. As the doctoradvances the device through the body, the obturator expands the pathwaycreated by the access needle. When the device reaches the desired area,the practitioner removes the safety needle and the obturator from thedilator, leaving the dilator in place. The practitioner then pushes thechest tube through the dilator and removes the dilator, leaving thechest tube in the desired location.

Problems arise with these types of trocars, however, because theobturator does not actually work very well in expanding the pathwaycreated by the relatively small access needle. The skin provides a toughmembrane that resists expansion, and additional skin nicks (using aseparate scalpel) are required around the access needle to allow theobturator to properly expand the skin layer and continue to penetratedeeper into the body.

To address this issue, other groups of trocars employ a retractableblade instead of an access needle. The blade is used to create a largerskin nick and advance through other tissues as needed until reaching thedesired location. The obturator easily expands the pathway as it passesthrough the skin layer while the practitioner advances the device, andthen the blade is retracted and the blade/obturator combination isremoved, leaving the dilator in place for the chest tube.

While these groups of trocars address the issue of requiring anadditional scalpel to allow the obturator to expand the skin layer, theydo not include the access needle that prevents the doctor fromprogressing too quickly or too far and causing harm to the patient.Without the access needle as part of the system, the patient is at agreater risk of complications.

What is needed in the market is an all-in-one trocar device thatprovides the ability to create a skin nick and maintain safety as thedevice is inserted deeper into the body, while quickly accessing thedesired location for chest tube placement.

BRIEF SUMMARY OF THE INVENTION

Benefits achieved in accordance with principles of the disclosedinvention include a device that provides access to interior bodyregions.

Some aspects of the present invention relate to a safety needle, a bladeassembly, an obturator assembly, a cannula assembly, and a handleassembly. The safety needle, blade assembly, obturator assembly, cannulaassembly, and handle assembly are assembled to create an access device.

In some aspects of the present invention, the handle assembly furtherincludes an actuator assembly and a lock assembly.

In other aspects of the present invention, the safety needle includes ahub through which fluid may be drawn in order to confirm the accessdevice has reached the proper location within the body.

In further aspects of the present invention, the blade assembly andobturator assembly are fixed relative to the handle assembly and theactuator assembly and lock assembly are moveable relative to the handleassembly.

In additional aspects of the present invention, moving the actuatorassembly relative to the handle assembly may expose blades through bladeslots located on the blade assembly.

In yet other aspects of the present invention, the lock assembly may bepositioned to permit or prevent movement of the actuator assemblyrelative to the handle assembly.

Yet other aspects of the present invention relate to a method ofaccessing interior body regions in which the safety needle assembly isadvanced through skin and into interior body regions to create apathway. The blades of the blade assembly are exposed and the bladeassembly is advanced into the skin to create a skin nick, after whichthe blades are covered. The access device is then advanced into thetissue, and the obturator assembly increases the diameter of the pathwaycreated by the safety needle. After the access device is in the properlocation, the safety needle assembly, blade assembly, and obturatorassembly are removed from the cannula assembly, leaving the cannulaassembly in the body to provide a conduit through which other devicesmay be inserted.

BRIEF SUMMARY OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthe specification, illustrate example embodiments and, together with thedescription, serve to explain the principles of the invention. In thedrawings:

FIG. 1 illustrates an access device according to aspects of the presentinvention;

FIG. 2 illustrates an exploded view of an access device according toaspects of the present invention;

FIG. 3 illustrates an exploded view of a handle assembly according toaspects of the present invention;

FIGS. 4A-B illustrate an exploded view of a blade assembly and actuatorassembly according to aspects of the present invention;

FIG. 5 illustrates a safety needle contacting skin according to aspectsof the present invention;

FIG. 6 illustrates a safety needle contacting a target according toaspects of the present invention;

FIG. 7 illustrates aspiration of a sample according to aspects of thepresent invention;

FIG. 8 illustrates releasing a lock assembly according to aspects of thepresent invention;

FIG. 9 illustrates exposing a blade according to aspects of the presentinvention;

FIG. 10 illustrates advancing a blade through skin and other regionsaccording to aspects of the present invention;

FIG. 11 illustrates removing a safety needle from an access deviceaccording to aspects of the present invention;

FIG. 12 illustrates an access device in the target position according toaspects of the present invention; and

FIG. 13 illustrates a cannula remaining in the target position accordingto aspects of the present invention.

DETAILED DESCRIPTION

FIG. 1 illustrates an access device according to aspects of the presentinvention.

As shown in the figure, access device 100 includes handle assembly 102,cannula assembly 104, obturator assembly 106, blade assembly 108, andsafety needle 110.

Specific aspects of handle assembly 102, cannula assembly 104, obturatorassembly 106, blade assembly 108, and safety needle 110 will be furtherdescribed with reference to FIGS. 2-4.

In general, safety needle 110 creates a pathway through the skin of apatient and into a target region. Then, blade assembly 108 creates askin nick to expand the size of the pathway to allow obturator assembly106 to increase the diameter of the pathway. Obturator assembly 106increases the diameter of the pathway when the user pushes handleassembly 102 toward the patient, urging obturator assembly 106 into thepathway. When obturator assembly 106 is in the target region, cannulaassembly 104 is disconnected from handle assembly 102, and cannulaassembly 104 is left within the patient for further procedural steps.

A detailed description of the assembly and operation of access devicewill now be described with reference to FIGS. 2-13.

FIG. 2 illustrates an exploded view of an access device according toaspects of the present invention.

As shown in the figure, safety needle 110 further includes a connection202, a hub 204, an outer cannula 206, an inner cannula 208, a sharp tip209, and a blunt tip 220.

Safety needle 110 is similar to the safety needle described in U.S. Pat.No. 9,743,952, and the description of the safety needle is incorporatedherein by reference. Therefore, safety needle 110 will not be describedhere in detail, but an overview of the operation of safety needle 110will be described below.

Safety needle 110 is also referred to as a “veress needle” by physiciansand other clinicians. Outer cannula 206 and inner cannula 208 aretypically made from a surgical grade stainless steel, however anymaterial suitable for patient contact may be used. Hub 204 and connector202 are typically made from a molded plastic, however any materialsuitable for connection to outer cannula 206 and inner cannula 208 maybe used.

Safety needle 110 is designed to prevent unnecessary needle sticks tothe patient because blunt tip 220 extends beyond sharp tip 209,therefore the first portion of safety needle 110 to contact a patient isblunt tip 220. When blunt tip 220 contacts the patient and safety needle110 continues to be pushed toward the patient, sharp tip 209 extendsforward until sharp tip 209 contacts the patient and begins to cuttissue. When sharp tip 209 has cut through tissue and reaches a pockedof air or fluid, blunt tip 220 is urged forward by a spring located inhub 204 until blunt tip 220 is distal to sharp tip 209, and again sharptip 209 is prevented from causing unwanted needle sticks to the patient.

Blade assembly 108 further includes a blade shaft 240, blades 242, alumen 244, a groove 246, and a groove 248.

Blade shaft 240 is a rigid tube and is preferably made of metal, howeverany other rigid material would suffice. Blade shaft 240 is connected toblades 242 such that there is no relative motion between the twocomponents. The connection is preferably a welded connection, howeverother connection means may be employed. For example, blade shaft 240 mayinclude one or more slots at its distal end and blades 242 may includeone or more matching slots such that blades 242 may be assembled on toblade shaft 240 by sliding slotted sections of blades 242 on to thecorresponding slots at the distal end of blade shaft 240.

Blades 242 are preferably constructed from metal, more preferably fromstainless steel, however any material suitable for medical applicationswould suffice. Blades 242 are designed to cut the skin and other tissuesof a patient, and as such are sufficiently sharp to cut skin and tissue.The specific shape, grind angles, and tip angles may be of anydimensions such that the effect of cutting skin and tissue may beaccomplished. Blades 242 are attached to blade shaft 240 as previouslydescribed.

Grooves 246 and 248 are located near the proximal end of blade shaft240. Grooves 246 and 248 are circumferential recesses cut into the outerwall of blade shaft 240, but grooves 246 and 248 do not breach the innerwall of blade shaft 240.

Lumen 244 is an opening that extends through the entire longitudinallength of blade shaft 240, providing a space through which safety needle110 can be inserted and removed.

Obturator assembly 106 further includes a proximal end 250, an obturatorshaft 254, a distal end 256, and a lumen 260. All components ofobturator assembly 106 are preferably made from plastic via eithermachining or molding processes, however any suitable material ormanufacturing method may be used to create obturator assembly 106 andits components.

Distal end 256 enlarges openings in skin and tissue, and furtherincludes blade slot 258. Blade slot 258 provides a pathway for blades242 to be deployed beyond the distal-most portion of distal end 256 andto be fully retracted within distal end 256. Distal end 256 is connectedobturator shaft 254 by any suitable means that would prevent relativemotion between the two components. In an alternate embodiment, distalend 256 and obturator shaft 254 may be a single component.

Obturator shaft 254 travels within the enlarged opening created bydistal end 256. As shown in the figure, obturator shaft 254 is a tubewith no slots or cuts in its outer diameter. In an alternate embodiment,obturator shaft 254 may contain slots or cuts that extend from the outerdiameter of obturator shaft 254 through the inner diameter of obturatorshaft 254. Including the slots or cuts may reduce weight and/ormanufacturing complexity or cost.

Proximal end 250 is connected to obturator shaft 254 by any means thatwould create a bond to prevent relative motion between the twocomponents. Proximal end 250 further includes shelf 252 such that shelf252 causes the cross section of proximal end 250 to be asymmetric. Shelf252 prevents relative motion between proximal end 250 and handleassembly 102 and permits proximal end 250 to be inserted into handleassembly 102 in only one orientation.

Lumen 260 is an opening that extends through the entire longitudinallength of obturator assembly 106, providing a space through which bladeassembly 108 can be inserted and removed.

Cannula assembly 104 further includes a cannula hub 262, a cannula shaft264, a protrusion 266, and a lumen 268. All components of cannulaassembly 104 are preferably made from plastic via either machining ormolding processes, however any suitable material or manufacturing methodmay be used to create cannula assembly 104 and its components.

Cannula hub 262 is connected to cannula shaft 264 by any means thatwould create a bond to prevent relative motion between the twocomponents. Cannula hub 262 further includes a protrusion 266 that issized and configured to fit within a slot on handle assembly 102. Asshown in the figure, one protrusion 266 is included on cannula hub 262,however in an alternate embodiment more than one protrusion may beincluded.

Lumen 268 is an opening that extends through the entire longitudinallength of cannula assembly 104, providing a space through whichobturator assembly 106 can be inserted and removed.

Handle assembly 102 further includes an actuator assembly 210, a lockassembly 212, a handle half 214, a handle half 216, a cannula slot 222,a cannula slot tab 224, a safety slot 226, a user grip 228, an indicator230, and assembly holes 232. Actuator assembly 210 and lock assembly 212will be further described with reference to FIG. 3.

Handle half 214 and 216 are preferably made from plastic via eithermachining or molding processes, however any suitable material ormanufacturing method may be used. Handle half 214 and handle half 216each include at least one assembly hole 232 such that when handle half214 and handle half 216 are assembled together, corresponding assemblyholes 232 line up with each other. Assembly holes 232 may be threadedsuch that a threaded connector could be used to connect correspondingassembly holes 232. In an alternate embodiment, assembly holes 232 maybe unthreaded such that an unthreaded connector may be used to connectcorresponding assembly holes 232. In yet another alternate embodiment,assembly holes 232 could be replaced with snap fit connections.

Cannula slot 222 is a groove that extends from the outer wall of handlehalf 216 through the inner wall of handle half 216. Cannula slot 222begins at the distal end of handle half 216 and extends parallel to thelongitudinal axis of handle assembly 102. Then cannula slot 222 extendscircumferentially around handle half 216. As shown in the figure,cannula slot 222 is shaped like an “L”, however in alternate embodimentscannula slot 222 may be shaped differently. Cannula slot 222 is sizedand configured to receive protrusion 266. As shown in the figure,cannula slot 222 is locate on handle half 216, however there may beanother cannula slot 222 located on handle half 214.

Cannula slot tab 224 is a tab disposed on the circumferential portion ofcannula slot 222. Cannula slot tab 224 may include a living hinge toallow cannula slot tab to flex when subjected to a force. Cannula slottab 224 is sized and configured to contact protrusion 266.

Safety slot 226 is located on the proximal end of handle assembly 102.Safety slot 226 is sized and configured to receive hub 204 of safetyneedle 110.

User grip 228 is the portion of handle assembly 102 that will be held bythe user. The size, shape, and configuration of user grip 228 as shownin the figure is a preferred embodiment, however any alternate sizes,shapes, or configurations of user grip 228 that allow a user to griphandle assembly 102 may be implemented.

Indicator 230 is disposed on handle half 216 and is a visual indicatorof the position of lock assembly 212. Indicator 230 may be triangular asshown in the figure, but any other shape sufficient to provideindication to a user may be used. In some embodiments, indicator 230 maybe molded in to the plastic of handle half 216, however in otherembodiments indicator 230 may be added to handle half 216 after themolding process. In those other embodiments, indicator 230 may be asticker affixed to handle half 216 or a more permanent marking like ink,paint, or dye. As shown in the figure, indicator 230 is located onhandle half 216, however in other embodiments indicator 230 may belocated on one or both of handle half 214 and 216.

To assemble access device 100, blade assembly 108 is assembled toobturator assembly 106. This assembly can be accomplished by insertingthe proximal end of blade assembly 108 into the distal end of lumen 260.The combination of blade assembly 108 and obturator assembly 106 is thenassembled into handle assembly 102. Safety needle 110 is then insertedthrough lumen 244 and hub 204 rests in safety slot 226. Cannula assembly104 is then attached to handle assembly 102 by inserting protrusion 266into cannula slot 222 first in the longitudinal direction, and then byrotating cannula assembly 104 such that protrusion 266 follows cannulaslot 222. When protrusion 266 contacts cannula slot tab 224, cannulaslot tab deflects to allow protrusion 266 to be rotated beyond cannulaslot tab 224. When protrusion 266 is past cannula slot tab 224, cannulaslot tab 224 returns to its original position. Additional assemblydetails will be further described with reference to FIGS. 3-4.

FIG. 3 illustrates an exploded view of a handle assembly according toaspects of the present invention.

As shown in the figure, handle half 214 further includes a longitudinalslot 302, a transverse slot 304, a window 305, a locking slot 306, and aprojection 308. Handle half 216 further includes a longitudinal slot310, a transverse slot 312, a window 313, a locking slot 314, and aprojection 316. Actuator assembly 210 includes an actuator tab 318, anactuator tab 320, a trigger 322, a lumen 324, a flat section 328, anassembly window 330, and an actuator stem 332. Lock assembly 212includes a locking rail 334, a locking rail 336, a visual indicator 338,a button 340, a button 342, a locking tab 344, a locking stem 345, alocking tab 346, a locking stem 347, a locking aperture 348, a stem 350,and a safety needle lock 352.

Actuator assembly 210 and lock assembly 212 are preferably made fromplastic via either machining or molding processes, however any suitablematerial or manufacturing method may be used.

Longitudinal slot 302 is a recess within the inner wall of handle half214, and longitudinal slot 302 is sized and configured to slidablyreceive actuator tab 318.

Transverse slot 304 is a recess within the inner wall of handle half214, and transverse slot 304 is sized and configured to slidably receivelocking rail 334.

Window 305 is a cut that extends through transverse slot 304 from theinner wall of handle half 214 through the outer wall of handle half 214,and window 305 is sized and configured to slidably receive button 342.

Locking slot 306 is a recess within the inner wall of handle half 214,and locking slot 306 is connected to, and extends from, transverse slot304. Locking slot 306 is sized and configured to slidably receivelocking stem 347.

Projection 308 is a protrusion within locking slot 306, and projection308 is sized and configured to interact with locking tab 346.

Longitudinal slot 310 is a recess within the inner wall of handle half216, and longitudinal slot 310 is sized and configured to slidablyreceive actuator tab 320.

Transverse slot 312 is a recess within the inner wall of handle half216, and transverse slot 312 is sized and configured to slidably receivelocking rail 336.

Window 313 is a cut that extends through transverse slot 312 from theinner wall of handle half 216 through the outer wall of handle half 216,and window 313 is sized and configured to slidably receive button 340.

Locking slot 314 is a recess within the inner wall of handle half 216,and locking slot 314 is connected to, and extends from, transverse slot312. Locking slot 314 is sized and configured to slidably receivelocking stem 345.

Projection 316 is a protrusion within locking slot 314, and projection316 is sized and configured to interact with locking tab 344.

Actuator tab 318 and actuator tab 320 are projections that extend fromthe main body of actuator assembly 210. Actuator tab 318 is sized andconfigured to fit within longitudinal slot 302, and actuator tab 320 issized and configured to fit within longitudinal slot 310. The length ofactuator tabs 318 and 320 is shorter than the lengths of longitudinalslots 302 and 310. The difference in lengths allows actuator tab 318 toslide within longitudinal slot 302 and actuator tab 320 to slide withinlongitudinal slot 310.

Trigger 322 is a projection that extends from the main body of actuatorassembly 210, and trigger 322 is sized and configured to allow at leastone of the user's fingers to pull on trigger 322.

Lumen 324 is an opening that extends from the proximal end of actuatorassembly 210 through the distal end of actuator assembly 210. Lumen 324is sized and configured to provide space in which other components maybe assembled and manipulated.

Flat section 328 is located near the distal end of lumen 324. Flatsection 328 is an area that is not rounded to provide for easierassembly of components such that one or more components may only beassembled in one orientation.

Assembly window 330 is a cut that extends from the outer wall ofactuator assembly 210 through the inner wall of actuator assembly 210,providing access to lumen 324 from an axis transverse to thelongitudinal axis of actuator assembly 210. Assembly window 330 providesfor easier manufacturing by allowing increased access to componentsduring the assembly process.

Actuator stem 332 is a projection that extends along the longitudinalaxis of actuator assembly 210. Actuator stem is sized and configured tofit within and through locking aperture 348 on lock assembly 212.

Locking rail 334 and locking rail 336 are projections that extend fromthe main body of lock assembly 212. Locking rail 334 is sized andconfigured to fit within transverse slot 304, and locking rail 336 issized and configured to fit within transverse slot 312. The length oflocking rails 334 and 336 is shorter than the lengths of transverseslots 304 and 312. The difference in lengths allows locking rail 334 toslide within transverse slot 304 and locking rail 336 to slide withintransverse slot 312.

Visual indicator 338 is a portion of locking rail 336 that can be viewedthrough window 313 based on the position of lock assembly 212. Visualindicator 338 may be a different color than the rest of lock assembly212 or actuator assembly 210 such that the user can see the colordifference when visual indicator 338 is viewable through window 313.Another visual indicator may be included on locking rail 334 such thatit would be viewable through window 305.

Button 340 and button 342 are projections that extend transversely fromlocking rails 336 and 334, respectively. Buttons 340 and 342 may beribbed to provide a surface for a user to manipulate. Button 342 issized and configured to extend through window 305, and button 340 issized and configured to extend through window 313. Thus, when a usermanipulates button 340 or 342, locking rails 334 and 336 may move up ordown within transverse slots 304 and 312 depending on the direction ofthe force applied by the user, which causes lock assembly 212 to move upor down as well.

Locking stem 345 and locking stem 347 are projections that extend fromthe main body of lock assembly 212. Locking stem 345 is sized andconfigured to slidably fit within locking slot 314, and locking stem 347is sized and configured to slidably fit within locking slot 306. Thelengths of locking stems 345 and 347 is shorter than the length oflocking slots 306 and 314. The difference in lengths allows locking stem345 to slide within locking slot 314 and locking stem 347 to slidewithin locking slot 306.

Locking tab 344 and locking tab 346 are projections that extend fromlocking stem 345 and locking stem 347, respectively. Locking tab 344 issized and configured to contact projection 316 and locking tab 346 issized and configured to contact projection 308 such that a force isrequired to move locking tabs 344 and 346 past projections 316 and 308,respectively.

Locking aperture 348 is an opening located within lock assembly 212 thatis aligned with the longitudinal axis of lock assembly 212. Lockingaperture 348 is sized and configured to allow actuator stem 332 to passthrough locking aperture 348 when locking aperture 348 and actuator stem332 are coaxial with each other.

Stem 350 is a projection that extends proximally from the main body oflock assembly 212. Stem 350 provides a base for safety needle lock 352.Safety needle lock 352 is a semi cylindrical projection extending fromstem 350. Safety needle lock 352 is sized and configured to interactwith hub 204 of safety needle 110.

FIGS. 4A-B illustrate an exploded and assembled view of a bladeassembly, actuator assembly, and obturator assembly according to aspectsof the present invention.

As shown in the figures, additional components used for assembly includea spring rest 402, washers 408 and 410, retaining rings 414 and 416, anda spring 418.

Spring rest 402 further includes a hole 404 and a threaded hole 406.Spring rest 402 is preferably molded or machined from plastic, howeverany other suitable materials would suffice. Spring rest 402 acts as astop for the proximal end of spring 418 such that when a compressionforce is applied to spring 418, spring rest 402 remains stationary anddoes not permit the proximal end of spring 418 to move. Spring rest 402is also sized and configured to fit within assembly window 330. Thelongitudinal length of spring rest 402 is shorter than the longitudinallength of assembly window 330, thus allowing relative linear motionbetween spring rest 402 and actuator assembly 210.

Hole 404 is an opening that extends from the proximal end of spring rest402 through the distal end of spring rest 402. Hole 404 is sized andconfigured to allow blade shaft 240 to pass through hole 404. Thecentral axis of threaded hole 406 is perpendicular to the central axisof hole 404. FIG. 4A shows one hole 406, however there is a second hole406 located 180 degrees opposite the threaded hole 406 shown in thefigure. Threaded hole 406 is sized and configured to receive a threadedconnector that is assembled through assembly holes 232. When a threadedconnector is assembled to threaded hole 406 through assembly holes 232,spring rest 402 becomes fixed to handle assembly 102.

Retaining rings 414 and 416 are preferably metal components sized andconfigured to fit within grooves 246 and 248, respectively. The outerdiameter of retaining rings 414 and 416 is larger than the outerdiameter of blade shaft 240. Retaining rings 414 and 416 are notcomplete cylinders, and the free ends of retaining rings 414 and 416flex slightly when assembling retaining rings 414 and 416 to grooves 246and 248.

Washers 408 and 410 are preferably standard metal washers with an innerdiameter sized and configured to fit around the outer diameter of bladeshaft 240. The inner diameter of washers 408 and 410 is smaller than theouter diameter of retaining rings 414 and 416, thus when washers 408 and410 contact retaining rings 414 and 416, washers 408 and 410 cannot movepast retaining rings 414 and 416.

Spring 418 is preferably a standard helical spring with an innerdiameter sized and configured to fit around the outer diameter of bladeshaft 240 and retaining rings 414 and 416. The outer diameter of spring418 is smaller than the outer diameter of washers 406 and 408.

FIG. 4B shows a cross-section taken along line A-A from FIG. 4A. Asshown in FIG. 4B, proximal end 250 of obturator assembly 106 furtherincludes a shelf 420. Shelf 420 is a cylindrical opening within proximalend 250 that is sized and configured to allow blade shaft 240 to extendthrough the opening. Shelf 420 is also sized and configured to contactspring 418.

To assemble actuator assembly 210, blade assembly 108, and obturatorassembly 106, first blade assembly 108 is inserted into obturatorassembly 106. To assemble, and with respect to FIG. 2 and FIG. 4, theproximal end of blade shaft 240 is inserted into lumen 260, and bladeassembly 108 can be advanced through lumen 260 until blades 242 contactdistal end 256 and prevent blade assembly 108 from advancing further. Atthis point, the proximal end of blade shaft 240 extends beyond proximalend 250. Retaining ring 414 is then assembled to groove 246. Spring 418is then placed over retaining ring 414 and advanced toward proximal end250 until the distal end of spring 418 contacts shelf 420.

Proximal end 250 is then inserted into lumen 324 of actuator assembly210. Proximal end 250 can only be inserted in one orientation for properassembly such that shelf 252 contacts flat section 328. Proximal end 250may be adhered to actuator assembly 210 at this point in the process,however the connection may occur later in the assembly process.

Washer 408 is then placed over blade shaft 240 in one of two ways.First, washer 408 may be maneuvered through assembly window 330 andplaced over blade shaft 240. Second, washer 408 may be dropped throughthe proximal end of lumen 324 and over blade shaft 240 such that wash408 resets on retaining ring 414.

Spring rest 402 is then maneuvered through assembly window 330 and bladeshaft 240 is placed through hole 404. In order to insert blade shaft 240through hole 404 it may be necessary to compress spring 418. Ifcompression of spring 418 is necessary, spring 418 must remaincompressed while washer 410 is placed over blade shaft 240 and on top ofspring rest 402, and while retaining ring 416 is connected to groove248. After retaining ring 416 is connected to groove 248, spring rest402 cannot move relative to blade assembly 108.

To complete the assembly of access device 100, and with reference toFIGS. 2-3, the assembled actuator assembly 210, blade assembly 108, andobturator assembly 106 is then placed on handle half 214 such thatactuator tab 318 is within longitudinal slot 302. Then, locking rail 334of lock assembly 212 is placed on handle half 214 such that locking rail334 is within transverse slot 304. In addition, locking tab 346 may beplaced on handle half 214 such that locking tab 346 is resting on top ofprojection 308.

In order to secure actuator assembly 210 in place, a threaded connectormay be assembled through assembly hole 232 on handle half 214 that islongitudinally coaxial with threaded hole 406 of spring rest 402. Thethreaded connector would engage both handle half 214 and spring rest 402such that actuator assembly 210 would not be dislodged from handle half214 during the rest of the assembly process.

Subsequently, handle half 216 may be assembled to handle half 214 byaligning longitudinal slot 310 with actuator tab 320, transverse slot312 with locking rail 336, and locking tab 344 with projection 316.After handle half 216 is properly placed, threaded connectors may beused to connect handle half 216 to handle half 214 by threading thethreaded connectors through assembly holes 232 that are longitudinallycoaxial with each other. An additional threaded connector may be used toengage handle half 216 and another threaded hole 406 of spring rest 402such that spring rest 402 is connected to both handle half 214 andhandle half 216.

After the threaded connections are complete, spring rest 402 and bladeassembly 108 are in a fixed position relative to actuator assembly 210.Additionally, because the locking tab 346 is resting on top ofprojection 308 and locking tab 344 is resting on top of projection 316,locking aperture 348 is not coaxially aligned with actuator stem 332. Assuch, if a user attempted to pull trigger 322, actuator assembly 210would not move relative to handle assembly 102 because actuator stem 332would collide with lock assembly 212 just below locking aperture 348,preventing any movement.

Cannula assembly 104 may then be assembled to handle assembly 102 byinserting the combination of obturator assembly 106 and blade assembly108 through lumen 268 until protrusion 266 contacts handle assembly 102.Cannula assembly 104 is then rotated until protrusion 266 is in linewith cannula slot 222, and then cannula assembly 104 is advanced furthertoward handle assembly 102 with protrusion 266 within cannula slot 222.When protrusion 266 again contacts handle assembly 102, cannula assembly104 is then rotated such that protrusion 266 continues to follow cannulaslot 222. Protrusion 266 will then contact cannula slot tab 224. Cannulaassembly 104 is rotated further such that protrusion 266 forces cannulaslot tab 224 to elastically deform. When protrusion 266 passes cannulaslot tab 224, cannula slot tab 224 returns to its original position,thus preventing cannula assembly 104 from being removed from handleassembly 102 unless a user reverses the steps required to assemblecannula assembly 108 to handle assembly 102.

Safety needle 110 is then assembled to access device 100 by insertingouter cannula 206 through lumen 244 until hub 204 contacts safety needlelock 352. To continue assembly, lock assembly 212 must be moved downwardby pressing one or both of buttons 340 and 342 to urge lock assembly 212downward. By doing so, locking tab 346 engages with projection 308 andlocking tab 344 engages with projection 316. In order for locking tab346 to move past projection 308, locking stem 347 must elasticallydeform. Likewise, in order for locking tab 344 to move past projection316, locking stem 345 must elastically deform. After locking tabs 346and 344 have passed projections 308 and 316, respectively, locking stems345 and 347 return to their original configurations.

With lock assembly 212 in the downward, or unlocked, position, hub 204of safety needle 110 may move past safety needle lock 352. When safetyneedle 110 can no longer move toward handle assembly 210, lock assembly212 may be returned to the upward, or locked, position, by pushing oneor both of buttons 340 and 342 upward until locking tabs 346 and 344 areabove projections 308 and 316, respectively. With lock assembly in thelocked position, safety needle lock 352 engages hub 204 such that hub204 cannot move relative to handle assembly 210.

The operation of the components discussed above will now be describedwith reference to FIGS. 5-13.

FIG. 5 illustrates a safety needle contacting skin according to aspectsof the present invention.

Prior to inserting access device 100 into a patient, a user willtypically palpate the skin 502 to determine the appropriate insertionpoint to approach target 504. Target 504 is typically an area in thebody filled with fluid that needs to be drained. Once the desiredlocation is found, the user begins to insert access device 100.

When inserting access device 100 into the patient, safety needle 110 isthe first component to contact skin 502. Pushing safety needle 110against skin 502 causes inner cannula 208 to retract, exposing sharp tip209 to skin 502. As the user continues to push access device 100, sharptip 209 cuts through skin 602 and any other soft tissues including, butnot limited to, muscle, fat, and fascia.

FIG. 6 illustrates a safety needle contacting a target according toaspects of the present invention.

As the user continues to push access device 100, sharp tip 209 willeventually reach the boundary of target 504, and sharp tip 209 willpuncture target 504.

FIG. 7 illustrates aspiration of a sample according to aspects of thepresent invention.

After sharp tip 209 punctures fluid filled target 504, the resistancefrom skin and tissue that exposed sharp tip 209 is eliminated and blunttip 220 extends beyond sharp tip 209. A skilled user can sense the dropin resistance and will then seek to confirm that safety needle 110 is inthe desired location. To confirm that safety needle 110 is in target504, the user will attach a fluid drainage device to hub 202, and thenthe user will attempt to draw fluid from the area. If the desired fluidis drawn from the area, the user may continue with the procedure. If thedesired fluid is not drawn from the area, the user may need to continuein attempts to find the desired location.

FIG. 8 illustrates releasing a lock assembly according to aspects of thepresent invention.

After the user confirms safety needle 110 is in the desired location,the user must release lock assembly 212 to continue with the procedure.To release lock assembly 212, the user must push button 340 and/orbutton 342 down. Referring back to the discussion of FIG. 3, pushingbuttons 340 and/or 342 down will move lock assembly down as locking tabs344 and 346 move past projections 308 and 316. The user may hear anaudible click when lock assembly 212 has reached the unlocked position.Additionally, the user may see that button 340 will line up withindicator 230. Furthermore, the user may see visual indicator 338through window 313. Visual indicator 230 may be a bright color to alertthe user that lock assembly 212 is in the unlocked position. When lockassembly 212 is in the unlocked position, locking aperture 248 islongitudinally coaxial with actuator stem 332. Furthermore, when lockassembly 212 is in the unlocked position, safety needle lock 352 nolonger prohibits longitudinal movement of safety needle 110.

FIG. 9 illustrates exposing a blade according to aspects of the presentinvention.

With lock assembly 212 in the unlocked position, the user will then pulltrigger 322 proximally. Referring to FIG. 3, when the user pulls trigger322 in the proximal direction, actuator stem 332 extends through lockingaperture 248. Referring back to FIG. 4B, when the user pulls trigger 322in the proximal direction, spring 418 is compressed as obturatorassembly 106 moves proximally with trigger 322 and actuator assembly210. Because blade assembly 108 is fixed to spring rest 402, and springrest 402 is fixed to handle assembly 102, blade assembly 108 remainsstationary as obturator assembly 106 moves in the proximal direction. Asobturator assembly 106 moves in the proximal direction, distal end 256moves in the proximal direction as well, and blades 242 are exposedthrough blade slot 258.

FIG. 10 illustrates advancing a blade through skin and other regionsaccording to aspects of the present invention.

After blades 242 are exposed, the user will push access device furtherinto skin 502 such that blades 242 expand the size of the pathwaycreated by safety needle 110. To keep blades 242 exposed as the useradvances access device 100, the user must continue to squeeze trigger332. The user may choose to keep blades 242 exposed until reachingtarget 504.

Alternatively, the user may choose to release trigger 332 to coverblades 242 and move lock assembly 212 to the locked position, and thenuse the blunt distal end 256 to expand the pathway.

FIG. 11 illustrates removing a safety needle from an access deviceaccording to aspects of the present invention.

After distal end 256 reaches target 504, safety needle 110 can beremoved from access device 100. To remove safety needle 110, lockassembly 212 must be in the unlocked position such that hub 204 is notconstrained by safety needle lock 352. After lock assembly 212 is placedin the unlocked position, the user can remove safety needle 110 bypulling hub 204 in the proximal direction until safety needle 110 iscompletely removed.

FIG. 12 illustrates an access device in the target position according toaspects of the present invention.

After safety needle 110 is removed, cannula shaft 264 must be positionedwithin target 504. If cannula shaft 264 was not positioned within target504 when safety needle 110 was removed, the user must push access device100 distally until cannula shaft 264 is positioned within target 504.

FIG. 13 illustrates a cannula remaining in the target position accordingto aspects of the present invention.

After cannula shaft 264 is properly positioned within cannula shaft 264,cannula assembly 104 can be removed from handle assembly 102. To removecannula assembly 104 from handle assembly 102, and with reference toFIG. 2, the user will rotate cannula assembly 104 with respect to handleassembly 102 such that protrusion 266 moves within cannula slot 222 pastcannula slot tab 224. Then the user will hold cannula shaft 264stationary while pulling user grip 228 distally such that protrusion 266exits cannula slot 222. The user will continue to pull user grip 228distally, which will remove obturator assembly 106 and blade assembly108 from lumen 268.

Then, cannula assembly 104 is left in the patient with lumen 268extending from target 504 outside of skin 502, providing access totarget 504. The user will typically then place a catheter through lumen268 to reach target 504. After the catheter is in the desired location,cannula assembly 104 is then removed from the patient, and the usercompletes the procedure by closing the skin around the catheter.

The foregoing description of various preferred embodiments have beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formsdisclosed, and obviously many modifications and variations are possiblein light of the above teaching. The example embodiments, as describedabove, were chosen and described in order to best explain the principlesof the invention and its practical application to thereby enable othersskilled in the art to best utilize the invention in various embodimentsand with various modifications as are suited to the particular usecontemplated. It is intended that the scope of the invention be definedby the claims appended hereto.

1-9. (canceled)
 10. A method of accessing interior body regions,comprising: providing an access device, defining: an actuator assemblyand a lock assembly at least partially housed within a handle assembly,a safety needle in slidable communication with a blade assembly and saidlock assembly, said blade assembly in slidable communication with anobturator assembly, said obturator assembly fixed to said actuatorassembly, and a cannula assembly in slidable and rotatable communicationwith said handle assembly; advancing said safety needle through a skinlayer and into said interior body regions, creating a pathway; pushing abutton on said lock assembly toward a user grip of said handle assembly,wherein said pushing moves said lock assembly toward said user grip,causing a locking aperture within said lock assembly to becomelongitudinally coaxial with an actuator stem of said actuator assembly;pulling a trigger of said actuator assembly, wherein said pulling movessaid actuator assembly toward said user grip, causing said actuator stemto extend through said locking aperture, wherein said pulling moves saidobturator assembly toward said user grip, exposing a blade of said bladeassembly; advancing said blade against said skin layer by pushing saidaccess device toward said skin layer, cutting said skin layer to createa skin nick and increasing the size of said pathway; releasing saidtrigger, wherein said releasing moves said obturator assembly away fromsaid user grip, covering said blade, and wherein said releasing removessaid actuator stem from said locking aperture; pushing said button awayfrom said user grip, wherein said pushing moves said lock assembly awayfrom said user grip and causes said locking aperture to move out of alongitudinally coaxial alignment with said actuator stem; rotating saidcannula assembly relative to said handle assembly, wherein said rotatingcauses a protrusion on a cannula hub to disengage from a cannula slottab on said handle assembly and follow a cannula slot on said handleassembly; and removing said cannula assembly from said handle assemblyby translating said cannula assembly relative said handle assembly,wherein said translating causes said protrusion to follow said cannulaslot on said handle assembly.
 11. The method of claim 10, furthercomprising confirming the location of said safety needle by aspiratingfluid through said safety needle after said safety needle reaches saidinterior body regions.
 12. The method of claim 10, wherein when saidlock assembly moves toward said user grip, a safety needle lockdisengages with said safety needle such that said safety needle canfreely translate and rotate within a lumen of said blade assembly. 13.The method of claim 12, wherein when said lock assembly moves towardsaid user grip, a locking tab on said lock assembly engages with aprojection on said handle assembly such that said lock assembly remainsin an unlocked position.
 14. The method of claim 13, wherein when saidlock assembly moves away from said user grip, said locking tab engageswith said projection such that said lock assembly remains in a lockedposition.